O48782 (HMOX1_ARATH) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Heme oxygenase 1, chloroplastic
Short name=AtHO1
EC=1.14.99.3

Alternative name(s):
Protein GENOMES UNCOUPLED 2
Protein REVERSAL OF THE DET PHENOTYPE 4

Gene names

Name:	HO1
Synonyms:	GUN2, HY1, HY6, TED4
Ordered Locus Names:	At2g26670
ORF Names:	F18A8.4

Organism

Arabidopsis thaliana (Mouse-ear cress) [Reference proteome]

Taxonomic identifier

3702 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Viridiplantae › Streptophyta › Streptophytina › Embryophyta › Tracheophyta › Euphyllophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › malvids › Brassicales › Brassicaceae › Camelineae › Arabidopsis

Protein attributes

Sequence length	282 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Key enzyme in the synthesis of the chromophore of the phytochrome family of plant photoreceptors. Catalyzes the opening of the heme ring to form the open-chain tetrapyrrole biliverdin IX with the release of iron and carbon monoxide (CO). Produces specifically the biliverdin IX-alpha isomer. Can form complex with heme, is ferredoxin-dependent and its activity is increased in the presence of ascorbate. Plays a role in salt acclimation signaling. May affect the plastid-to-nucleus signaling pathway by perturbing tetrapyrrole synthesis. The plastid-to-nucleus signal plays an important role in the coordinated expression of both nuclear- and chloroplast-localized genes that encode photosynthesis-related proteins. Ref.1 Ref.2 Ref.8 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13 Ref.14 Ref.16 Ref.17 Ref.18
Catalytic activity	Heme + 3 AH2 + 3 O2 = biliverdin + Fe2+ + CO + 3 A + 3 H2O. Ref.1 Ref.13
Enzyme regulation	Activated by ascorbate. Ref.13
Subcellular location	Plastid › chloroplast Ref.1 Ref.16.
Tissue specificity	Widely expressed. Ref.2 Ref.14 Ref.17
Induction	By salt treatment. Down-regulated by jasmonate. Ref.13 Ref.15 Ref.17
Disruption phenotype	Long hypocotyl, incomplete chloroplast and leaf development, lack of photoreversible phytochromes and lack of phytochromobilin, the phytochrome chromophore. No cotyledon expansion in response to bright-red light. Increased levels of jasmonate (JA) and constitutive expression of JA-inducible defense genes. Increased sensitivity to salt stress and no acclimation response to salinity. Ref.1 Ref.2 Ref.7 Ref.8 Ref.9 Ref.10 Ref.11 Ref.14 Ref.15 Ref.17 Ref.18
Sequence similarities	Belongs to the heme oxygenase family.
Biophysicochemical properties	Kinetic parameters: KM=1.3 µM for hemin Ref.13 Ref.16 KM=1.9 µM for ferredoxin KM=420 µM for ascorbate pH dependence: Optimum pH is 7.2.
Sequence caution	The sequence AAK52998.1 differs from that shown. Reason: Erroneous initiation. Translation N-terminally extended.

Ontologies

Keywords
Biological process	Photosynthesis
Cellular component	Chloroplast Plastid
Coding sequence diversity	Alternative splicing
Domain	Transit peptide
Ligand	Heme Iron Metal-binding
Molecular function	Oxidoreductase
Technical term	Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	carotenoid biosynthetic process Inferred from mutant phenotype PubMed 22419743. Source: TAIR cellular response to UV-C Inferred from mutant phenotype PubMed 22419743. Source: TAIR chloroplast-nucleus signaling pathway Inferred from mutant phenotype Ref.9. Source: TAIR flavonoid biosynthetic process Inferred from mutant phenotype PubMed 22419743. Source: TAIR heme oxidation Inferred from electronic annotation. Source: InterPro photosynthesis Inferred from electronic annotation. Source: UniProtKB-KW phytochromobilin biosynthetic process Inferred from direct assay Ref.14. Source: TAIR regulation of meristem growth Inferred from genetic interaction PubMed 18424613. Source: TAIR
Cellular_component	chloroplast Inferred from direct assay Ref.1PubMed 18431481Ref.16. Source: TAIR
Molecular_function	heme binding Inferred from direct assay Ref.16. Source: TAIR heme oxygenase (decyclizing) activity Inferred from direct assay Ref.14Ref.16. Source: TAIR metal ion binding Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Alternative products

This entry describes 2 isoforms produced by alternative splicing. [Align] [Select]

Isoform 1 (identifier: O48782-1)

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

Isoform 2 (identifier: O48782-2)

The sequence of this isoform differs from the canonical sequence as follows:
     94-142: GEKETKSIEERPVAKWEPTVEGYLRFLVDSKLVYDTLELIIQDSNFPTY → D

Note: Derived from EST data. No experimental confirmation available.

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Transit peptide	1 – 54	54	Chloroplast Potential
	Chain	55 – 282	228	Heme oxygenase 1, chloroplastic		PRO_0000412185
Sites
	Metal binding	86	1	Iron (heme axial ligand) By similarity
Natural variations
	Alternative sequence	94 – 142	49	GEKET…NFPTY → D in isoform 2.		VSP_041652

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 [UniParc]. Last modified November 1, 1999. Version 2. Checksum: 65D9638890A3E8BA	FASTA	282	32,691
	10 20 30 40 50 60 MAYLAPISSS LSIFKNPQLS RFQFSSSSPN PLFLRPRIQI LSMTMNKSPS LVVVAATTAA 70 80 90 100 110 120 EKQKKRYPGE SKGFVEEMRF VAMRLHTKDQ AKEGEKETKS IEERPVAKWE PTVEGYLRFL 130 140 150 160 170 180 VDSKLVYDTL ELIIQDSNFP TYAEFKNTGL ERAEKLSTDL EWFKEQGYEI PEPTAPGKTY 190 200 210 220 230 240 SQYLKELAEK DPQAFICHFY NIYFAHSAGG RMIGRKVAER ILDNKELEFY KWDGELSQLL 250 260 270 280 QNVREKLNKV AEEWTREEKN HCLEETEKSF KYSGEILRLI LS
	Isoform 2 [UniParc]. Checksum: D5350323BB620A1E	FASTA	234	27,076
	10 20 30 40 50 60 MAYLAPISSS LSIFKNPQLS RFQFSSSSPN PLFLRPRIQI LSMTMNKSPS LVVVAATTAA 70 80 90 100 110 120 EKQKKRYPGE SKGFVEEMRF VAMRLHTKDQ AKEDAEFKNT GLERAEKLST DLEWFKEQGY 130 140 150 160 170 180 EIPEPTAPGK TYSQYLKELA EKDPQAFICH FYNIYFAHSA GGRMIGRKVA ERILDNKELE 190 200 210 220 230 FYKWDGELSQ LLQNVREKLN KVAEEWTREE KNHCLEETEK SFKYSGEILR LILS

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"The Arabidopsis photomorphogenic mutant hy1 is deficient in phytochrome chromophore biosynthesis as a result of a mutation in a plastid heme oxygenase." Muramoto T., Kohchi T., Yokota A., Hwang I., Goodman H.M. Plant Cell 11:335-348(1999) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA] (ISOFORM 1), FUNCTION, CATALYTIC ACTIVITY, SUBCELLULAR LOCATION, DISRUPTION PHENOTYPE. Strain: cv. Landsberg erecta.
[2]	"The Arabidopsis thaliana HY1 locus, required for phytochrome-chromophore biosynthesis, encodes a protein related to heme oxygenases." Davis S.J., Kurepa J., Vierstra R.D. Proc. Natl. Acad. Sci. U.S.A. 96:6541-6546(1999) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, TISSUE SPECIFICITY, DISRUPTION PHENOTYPE. Strain: cv. Columbia and cv. Landsberg erecta.
[3]	"Sequence and analysis of chromosome 2 of the plant Arabidopsis thaliana." Lin X., Kaul S., Rounsley S.D., Shea T.P., Benito M.-I., Town C.D., Fujii C.Y., Mason T.M., Bowman C.L., Barnstead M.E., Feldblyum T.V., Buell C.R., Ketchum K.A., Lee J.J., Ronning C.M., Koo H.L., Moffat K.S., Cronin L.A. , Shen M., Pai G., Van Aken S., Umayam L., Tallon L.J., Gill J.E., Adams M.D., Carrera A.J., Creasy T.H., Goodman H.M., Somerville C.R., Copenhaver G.P., Preuss D., Nierman W.C., White O., Eisen J.A., Salzberg S.L., Fraser C.M., Venter J.C. Nature 402:761-768(1999) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: cv. Columbia.
[4]	The Arabidopsis Information Resource (TAIR) Submitted (APR-2011) to the EMBL/GenBank/DDBJ databases Cited for: GENOME REANNOTATION. Strain: cv. Columbia.
[5]	"Empirical analysis of transcriptional activity in the Arabidopsis genome." Yamada K., Lim J., Dale J.M., Chen H., Shinn P., Palm C.J., Southwick A.M., Wu H.C., Kim C.J., Nguyen M., Pham P.K., Cheuk R.F., Karlin-Newmann G., Liu S.X., Lam B., Sakano H., Wu T., Yu G. , Miranda M., Quach H.L., Tripp M., Chang C.H., Lee J.M., Toriumi M.J., Chan M.M., Tang C.C., Onodera C.S., Deng J.M., Akiyama K., Ansari Y., Arakawa T., Banh J., Banno F., Bowser L., Brooks S.Y., Carninci P., Chao Q., Choy N., Enju A., Goldsmith A.D., Gurjal M., Hansen N.F., Hayashizaki Y., Johnson-Hopson C., Hsuan V.W., Iida K., Karnes M., Khan S., Koesema E., Ishida J., Jiang P.X., Jones T., Kawai J., Kamiya A., Meyers C., Nakajima M., Narusaka M., Seki M., Sakurai T., Satou M., Tamse R., Vaysberg M., Wallender E.K., Wong C., Yamamura Y., Yuan S., Shinozaki K., Davis R.W., Theologis A., Ecker J.R. Science 302:842-846(2003) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 1). Strain: cv. Columbia.
[6]	"Full-length cDNA from Arabidopsis thaliana." Brover V.V., Troukhan M.E., Alexandrov N.A., Lu Y.-P., Flavell R.B., Feldmann K.A. Submitted (MAR-2002) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 1).
[7]	"Different roles for phytochrome in etiolated and green plants deduced from characterization of Arabidopsis thaliana mutants." Chory J., Peto C.A., Ashbaugh M., Saganich R., Pratt L., Ausubel F. Plant Cell 1:867-880(1989) [PubMed] [Europe PMC] [Abstract] Cited for: DISRUPTION PHENOTYPE.
[8]	"Phytochrome-deficient hy1 and hy2 long hypocotyl mutants of Arabidopsis are defective in phytochrome chromophore biosynthesis." Parks B.M., Quail P.H. Plant Cell 3:1177-1186(1991) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[9]	"Signal transduction mutants of Arabidopsis uncouple nuclear CAB and RBCS gene expression from chloroplast development." Susek R.E., Ausubel F.M., Chory J. Cell 74:787-799(1993) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[10]	"Light-stimulated cotyledon expansion in Arabidopsis seedlings (the role of phytochrome b)." Neff M.M., Van Volkenburgh E. Plant Physiol. 104:1027-1032(1994) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[11]	"Interactions between hy1 and gun mutants of Arabidopsis, and their implications for plastid/nuclear signalling." Vinti G., Hills A., Campbell S., Bowyer J.R., Mochizuki N., Chory J., Lopez-Juez E. Plant J. 24:883-894(2000) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[12]	"Arabidopsis genomes uncoupled 5 (GUN5) mutant reveals the involvement of Mg-chelatase H subunit in plastid-to-nucleus signal transduction." Mochizuki N., Brusslan J.A., Larkin R., Nagatani A., Chory J. Proc. Natl. Acad. Sci. U.S.A. 98:2053-2058(2001) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[13]	"Expression and biochemical properties of a ferredoxin-dependent heme oxygenase required for phytochrome chromophore synthesis." Muramoto T., Tsurui N., Terry M.J., Yokota A., Kohchi T. Plant Physiol. 130:1958-1966(2002) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, CATALYTIC ACTIVITY, ENZYME REGULATION, BIOPHYSICOCHEMICAL PROPERTIES.
[14]	"Multiple heme oxygenase family members contribute to the biosynthesis of the phytochrome chromophore in Arabidopsis." Emborg T.J., Walker J.M., Noh B., Vierstra R.D. Plant Physiol. 140:856-868(2006) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, TISSUE SPECIFICITY, DISRUPTION PHENOTYPE.
[15]	"Phytochrome chromophore deficiency leads to overproduction of jasmonic acid and elevated expression of jasmonate-responsive genes in Arabidopsis." Zhai Q., Li C.B., Zheng W., Wu X., Zhao J., Zhou G., Jiang H., Sun J., Lou Y., Li C. Plant Cell Physiol. 48:1061-1071(2007) [PubMed] [Europe PMC] [Abstract] Cited for: INDUCTION, DISRUPTION PHENOTYPE.
[16]	"Characterization of the haem oxygenase protein family in Arabidopsis thaliana reveals a diversity of functions." Gisk B., Yasui Y., Kohchi T., Frankenberg-Dinkel N. Biochem. J. 425:425-434(2010) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, SUBCELLULAR LOCATION, BIOPHYSICOCHEMICAL PROPERTIES.
[17]	"Enzymatic ring opening of an iron corrole by plant-type heme oxygenases: unexpected substrate and protein selectivities." Gisk B., Bregier F., Krueger R.A., Broering M., Frankenberg-Dinkel N. Biochemistry 49:10042-10044(2010) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, TISSUE SPECIFICITY, INDUCTION, DISRUPTION PHENOTYPE.
[18]	"Evidence of Arabidopsis salt acclimation induced by up-regulation of HY1 and the regulatory role of RbohD-derived reactive oxygen species synthesis." Xie Y.J., Xu S., Han B., Wu M.Z., Yuan X.X., Han Y., Gu Q., Xu D.K., Yang Q., Shen W.B. Plant J. 66:280-292(2011) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBL GenBank DDBJ	AB021857 Genomic DNA. Translation: BAA77758.1. AB021858 mRNA. Translation: BAA77759.1. AF132475 Genomic DNA. Translation: AAD22107.1. AF132476 Genomic DNA. Translation: AAD22108.1. AC003105 Genomic DNA. Translation: AAB95301.2. CP002685 Genomic DNA. Translation: AEC07872.1. CP002685 Genomic DNA. Translation: AEC07873.1. AF327418 mRNA. Translation: AAG42008.2. AF375414 mRNA. Translation: AAK52998.1. Different initiation. AY129477 mRNA. Translation: AAM91063.1. BT002327 mRNA. Translation: AAN86160.1. AY087288 mRNA. Translation: AAM64841.1.
IPI	IPI00531937. IPI00891372.
PIR	T52457.
RefSeq	NP_001118392.1. NM_001124920.1. NP_180235.1. NM_128224.2.
UniGene	At.23645.
3D structure databases
ProteinModelPortal	O48782.
SMR	O48782. Positions 88-277.
ModBase	Search...
Protein-protein interaction databases
STRING	3702.AT2G26670.1-P.
Proteomic databases
PRIDE	O48782.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
GeneID	817208.
KEGG	ath:AT2G26670.
Organism-specific databases
TAIR	At2g26670.
Phylogenomic databases
eggNOG	NOG308332.
HOGENOM	HOG000265822.
InParanoid	O48782.
OMA	GGRMIGR.
PhylomeDB	O48782.
ProtClustDB	CLSN2683416.
Gene expression databases
Genevestigator	O48782.
Family and domain databases
Gene3D	1.20.910.10. 1 hit.
InterPro	IPR016053. Haem_Oase-like. IPR016084. Haem_Oase-like_multi-hlx. IPR016951. Haem_Oase_decyc_pln. [Graphical view]
Pfam	PF01126. Heme_oxygenase. 1 hit. [Graphical view]
PIRSF	PIRSF030219. Heme_Oase_decyc_pln. 1 hit.
SUPFAM	SSF48613. Heme_oxygenase. 1 hit.
ProtoNet	Search...

Entry information

Entry name

HMOX1_ARATH

Accession

Primary (citable) accession number: O48782
Secondary accession number(s): B3H4A6, Q7E9A5, Q9FPE3

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 27, 2011
Last sequence update:	November 1, 1999
Last modified:	May 1, 2013
This is version 87 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Plant Protein Annotation Program